That is also possible with a render target, but unnecessary in the most of cases. Decal actors works well when you want to leave an impact decal from weapons. Thats how people normally do it in a shooter game.
That might work, thanks :) Part of the reason I don't want to use individual decals is that I want the marks created to be permanent and additive - Eg. You scratch a surface and then scratch it again and again to reveal more of the underlying structure. I can't imagine it'd take long to start seeing issues with decal…
So yeah. I want unlimited instances of material dependent surface damage plastered over my level at runtime and I want it to be free(ish) This probably rules out traditional polygon decals (unless there's a magic buffer someone knows about? ) so my thoughts turn to ways of passing damage location information to shaders and…